Communication systems providing mobility for the users thereof are known. A well known example of the mobile communication systems is the public land line mobile network (PLMN), a cellular communication network being an example of the PLMN. Another example is a mobile communication system that is based, at least partially, on use of communication satellites.
The mobile network apparatus and/or user equipment such as a mobile station can be employed for provision of information regarding the geographical location of the user equipment and thus the user thereof. A mobile user equipment and thus the user thereof can be positioned by various different techniques. For example, substantially accurate geographical location information that associates with a user equipment can be obtained based on the known satellite based GPS (Global Positioning System). More accurate location information can be obtained through a differential GPS.
Another possibility is to use a location service that associates with a cellular telecommunications system for the provision of the location information. In this approach the cells or similar geographically limited radio access entities and associated controllers of the communication system are utilised in production of at least a rough location information estimate concerning the current location of the mobile user equipment. To improve the accuracy of the location information the communication system may be provided with specific location measurement units that provide more accurate data concerning the location of a user equipment within the service area of the cellular system. It is also possible to determine geographical location when the mobile user equipment is located within the coverage area of a visited or “foreign” network. The visited network may be made capable of transmitting the location of the mobile user equipment back to the home network, e.g. to support services that are based on location information or for the purposes of routing and charging.
The location data may be processed in a specific location service entity that is implemented either within the cellular system or connected thereto. The location data may also be processed in the user equipment that is provided with appropriate processing capacity. The location service entity provided by the communication system may serve different clients via an appropriate interface.
The location information may be used for various purposes, such as for location of a mobile telephone that has made an emergency call, for locating vehicles or given mobile subscribers and so on. In general, a client such as user equipment or another entity wishing to receive location information regarding user equipment may send a request for such information to the location service provision entity. The location service provisioning entity will then process the request, obtain the required data and generate an appropriate response.
An example of the provision of location information by a PLMN is described in more detail in 3rd Generation Partnership Project (3GPP) technical specifications, see e.g. 3GPP TS 23.271 version 4.2.0, titled “Functional stage 2 description of LCS”, June 2001.
According to the 3GPP specification a location service (LCS) server entity referred to as a Gateway Mobile Location Center (GMLC) is provided for managing the location services. The GMLC is for gathering and storing various data that may be used in the provision of location information for location service clients (LCS clients). The LCS Client may make use of that location information for various services/applications. A possible application comprises a LCS client arranged to provide location information in response to a request for non-call related location information. Such a request for location information is referred to in the 3GPP specifications as a non-call related MT-LR (Mobile Terminated Location Request).
Use of a so called “Authorized UE List” has been proposed. This list contains Mobile Subscriber ISDN (MSISDN) (ISDN—Integrated Services Digital Network) numbers or groups of MSISDNs which are authorised to initiate a location information provision procedure. That is, MSISDNs or groups of MSISDN are listed for which the LCS Client may issue a non-call related MT-LR. Separate lists of MSISDNs may be associated with each distinct external or non-call related client identity. Location information may be provided by the LCS server to the LCS client in response to a request for location information from a user with a MSISDN number that appears in the list.
The LCS Client who is external to the PLMN system may only be enabled to validly issue location information requests for those MSISDNs which are found on the “Authorized UE List”. That is, the LCS clients request may only be responded for subscribers who subscribe to the location services provided by the PLMN, as their MSISDNs would not otherwise appear on the list.
Requests from the LCS Client are authenticated based on a combination of a Client ID and password stored in a LCS Client profile at the LSC server (e.g. the GMLC) and authorized based on the “Authorized UE List”. That is, the LCS client is authorised to receive location information from the GMLC entity if the requesting user equipment (UE) is found from the list.
LCS clients are typically Application Service Providers (ASP) who are not a part of the PLMN system.
One important issue in Mobile Location Services (MLS) is the subscriber's privacy. In particular the user is able to define only broad privacy requirements which are stored in the home location register HLR. The current privacy requirements allow a user to define whether or not the user's location information can be provided and if so to which clients. Currently these privacy requirements have been handled by Mobile Services Switching Centre (MSC), GMLC, and the mobile terminal based on the information stored in the home location register. For example, Client screening is done in the GMLC (that is clients can request location information via the GMLC network operator) and in the MSC/VLR (that is clients can request for example a user's subscriber's location information) (VLR=Visitor Location Register).
The subscriber specific privacy parameter information is stored in the HLR and copied to VLR, if required. This information is generally called LCS privacy parameters. The problem with the existing system is that it is limited and inflexible.